ExpressJS: How to know when a request has finished?

req.on("close")

So simply

app.get('/keys/readresults/:keyname', basic_auth, function(req,res){
    res.writeHead(200, {'content-type': 'text/json'});
    var no = setInterval(
        go_to_database_and_get('stuff', function (database_replies) {
        res.write(database_replies)
    });
    ,5000);
    req.on("close", function() {
        clearInterval(no);
    });
});

req.on('close', ...) no longer works in Express 4. Use the on-finished middleware.